"Tolmachev Dol (Tomachev Plateau) is broad volcanic highland NE of Opala volcano that is dotted with numerous late-Pleistocene and Holocene cinder cones and associated lava flows. The cones and lava fields cover a broad area on both sides of scenic Lake Tolmachev, which lies in large depression halfway between Opala and Gorely volcanoes. The 1415-m-high Tolmachev stratovolcano of Pleistocene age lies on the SE side of the lake. A major explosive eruption took place about 4600 years ago from Chasa crater in the northern part of the plateau, during which about 1 cu km of rhyolitic tephra was ejected. The latest dated eruption at Tolmachev Dol occurred from a cinder cone in the NW part of the plateau about 1600-1700 years ago." -Smithsonian Volcano Archive